Various connection transport technologies have been developed in standards and deployed in networks. Examples of these connection transport technologies include time division multiplexed (TDM) circuits, such as Synchronous Digital Hierarchy (SDH) and Plesiochronous Digital Hierarchy (PDH), and packet virtual circuits, such as Frame Relay and X.25. Generally, these technologies create a connection comprising a single transport channel extending between two points in the network. Specifically, the connection is a series of links providing a single path that carries client packets. The client packets are transported along the connection such that the packets are delivered to the egress port in the same order as received at the ingress port. In addition, the connection transports these packets without any visibility into or knowledge of the packets' contents.
Traffic engineering enables service providers to optimize the use of network resources while maintaining service guarantees. Traffic engineering becomes increasingly important as service providers desire to offer transport services with performance or throughput guarantees. The single path nature of traditional connections limits the ability of the network operator to engineer the traffic in the network. Specifically, traffic engineering activities may be limited to the placement of large-capacity edge-to-edge tunnels, which limits the network operator's flexibility. Additional flexibility may be obtained by creating additional tunnels and using additional client layer functions to map client traffic to these tunnels. However, this may require each tunnel's primary and backup route to be reserved and engineered from edge-to-edge, which may make link capacity optimization awkward and complex.